DESCRIPTION: The cadherins are a family of cell surface proteins that mediate adhesion between embryonic cells. These molecules are expressed during the early formation of the vertebrate nervous system when the ectoderm, an epithelial sheet, undergoes the morphogenetic movements of neurulation to form the neuroepithelium of the neural tube. Previous studies have shown that perturbation of cadherin functions during neurulation, results in abnormal neural tube formation in Xenopus embryos. The proposed experiments will dissect further the function of cadherins during these first steps in the formation of the Xenopus nervous system. The role of proteins that interact with the cadherins inside the cell will be isolated and studied. The role of N-cadherin in mediating the cell rearrangements that underlie the formation of neural tube will be analyzed. The role of a F-cadherin, which is expressed in subregions of the neural tube, will be analyzed in order to determine how different regions of the neural tube are formed. Finally, new members of the cadherin family have been isolated that are expressed during neural tube formation, and the role of these molecules in the morphogenetic movements of neurulation will also be studied. The results from these experiments will provide insights in the molecular mechanisms that underlie neural tube formation, which should eventually lead to a better understanding of the etiology of neural tube defects.